Is distillation a purification or characterization technique

The atomic number, or number, is the described as the number of in the nucleus of an chemical element.

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

In the diagram here that represents the reaction, which reactant, a or b, is the limiting reagent?